Acoustic telegraph



(ModeL) 2 Sheets-Sheet 1.

J. H. IRWIN.

AOOUSTIG TELEGRAPH.

No. 367,042. Patented July 26, 1887.

(ModeL) 2 Sheets--Sheet 2.

J. H. IRWIN.

ACOUSTIC TELEGRAPH.

No. 367,042. Patented July 26, 1887.

flfifwt Invenibr:

UNITED STATES PATENT EEICE. f

JOHN H. IRVIN, OF PHILADELPHIA, PENNSYLVANIA.

ACOUSTIC TELEGRAPH.

SPECIFICATION forming part of Letters Patent No. 367,042, dated July 26,1887.

Application filed June 4, 1879.

To aZZ whom, it may concern.-

Be it known that I, JOHN H. IRWIN, ofPhiladelphia,in the countyofPhiladelphia and State of Pennsylvania, have invented new and usefulImprovements in Acoustic Telegraphs; and I do hereby declare thatthefollowiug is a full and exact description of the same.

Heretofore a principal obstacle to the satisfactory working of acoustictelegraphs arose from the incoustant action of the battery. When theresistance of the instrument has been -adjusted to a certainbatterytension, any variation in said tension will correspondinglyimpair the action of the instrument.

The object of the first part of my invention, therefore,is to make theinstrument self-regulating with reference to fluctuations in thebatterytension by means of an electromagnetic regulator in a short orlocal battery-circuit,in contradistinction to the method shown in mypatent of June 24, 1879, wherein the electromagnetic regulator is in thelonger linecircult.

The instrument to which I prefer to apply my present improvement is ofthe form heretofore patented by me, consisting of a pointed needleprovided with an elastic support and in pointed contact with a planesensitive to the impact of sound-waves, whereby the resistance at anattenuated place in the circuit is varied by andin accordance with thevariations imparted by the impact of sound-waves, though I do notpropose to limit my improvement to instruments of this descriptionfurther than may be necessary in view of my patent of June 24, 1879.

The second part of my invention relates to improvements inmagneto-electric telephones; and it consists in a disk-armaturesensitive to sound-waves placed in front of and within the magneticfield of an clectro-magnet, consisting ofa soft-iron core with a primarycoil in.

a short battery-circuit and a secondary coil wound over said primary andin connection with the line-wire, whereby the induction-coil is inclosedwithin the dimensions of a hand or portable instrument.

That others may fully understand my invention, I will particularlydescribe it, having reference to the accompanying drawings, whereinFigure l is a perspective View of one form of my instrument. Fig. 2 is alongitudinal section of my instrument. Fig. 3 is a longitudinal sectionof a modified form of my instrument.

A is the frame or casing of the instrument.

B is the plane, sensitive to the impact of sound-waves; and O is theneedle or conductor, provided with an electric support, D, which pressesthe needle against the sensitive plane with a certain pressure, whichmay be regulated by adjustment of the parts. The needle 0 is mounted inguides E E, whereby its mot-ions are entirely longitudinal, and alllateral Vibrations are restrained.

At the center of the sensitive plane or disk B, Iprefer to mounta pieceof carbon, b,against which the point of the needle or conductor C rests.The carbon 6 may be made adjustable as to the disk B to secure thedesired contact with the point of the needle or conductor 0; or theadjustment for said contact may be secured by adjustment of the parts13, O, and D, as before stated. The contact at I) having been adjustedfor a certain battery-tension, it is apparent that fluctuations of saidtension will cause the resistance at b to be too great or too little, asthe case may be. To obviate this undesirable effect I propose herein toemploy a eounterbalancing electro-1naguet which shall be excited by thesame battery and circuit, and therefore subject to fluctuations in powercorresponding to the fluctuations in battery-tension. F is the soft-ironcore of said magnet, and G is the helix surrounding the same and forminga part of the short batterycircuit H. I is the battery.

The direction of the current may be from the battery to the helix G,thence through the armature and needle or conductor G to the disk B andreturn to the battery. If the battery-current weakens, the excitement ofthe magnet F decreases and its attraction for the armature Dcorrespondingly decreases and the contact at b increases, permitting anincreased passage of electricity, thus maintaining an equilibrium ofacoustic effect.

An increase in battery-tension produces an opposite effect, increasingthe attraction for the armature D and correspondingly increasingresistance at b. The core F may be adjusted longitudinally in someconvenient manner, one good way being by means of a screw a scam-042like that shown at f. With instruments of this class it is common toemploy an induced line-current, and I place the inductioncoil K over theprimary coil or helix G; or, instead of placing the induction-coilaround the helix, the primary wire may be extended to an induction-coillocated elsewhere.

The conductor O may be pressed upon the disk by a spring independent ofthe armature, as shown in Fig. 3.

Fig. 4 represents a modification of structure,

wherein the needle-electrode is made movable and adjustable by means ofa screw-connection instead of the screw-adjustment of the carbonelectrode shown in Fig, 2.

Having described my invention, what claim as new is-- 4 1. The sensitivedisk B and conductor 0, held against said disk with an adjustable andelastic pressure, combined with a counterbalancing electro-magnet thehelix whereof is in the short battery-circuit H, in common with saiddisk and conductor, whereby the said magnet may be caused to vary thecontact at b in correspondence with the variations in thebatterytension.V

2. The sensitive disk 13, conductor 0, and

' elastic armature D, organized substantially as shown, combined withthe electro-magnet F, the helix G whereof is in the shortbattery-circuit H, in com mon with said disk and conductor, for thepurpose of self-regulation of resistance at b in correspondence withfluctuations of the battery-tension, as set forth.

'3. The sensitive disk B and conductor 0, moving longitudinally only inguides E, as set forth, combined with an elastic adjustable armature, Dto support said 00nd uctor in contact with said disk with substantiallyuniform pressure. 1

4. An eleetro=magnet, F, having its helix near one end and in connectionwith a short battery-circuit, combined with an inductioncoil, K, oversaid primary or helix, and a diskarmature, D, sensitive to sound-wavesin-the magnetic field in front of said magnet.

5. An electro-magnet, F, in a short or local battery-circuit, providedwith a tensio'n'regulator and with an inducti0n-coil wound over theprimary ofsaid magnet and in connection with the line'wire, combinedwith a flexible disk-armature sensitive to sound-waves, arranged nearthe pole or poles of said electromagnet, and therebyconstituting aportable transmitter in the primary circuit of the electro-magnet.

6. An electro'magnet, F, wound with an induction-coil over a flexiblearmature arranged near the pole or poles of said electro-magnet, and atransmitter'arranged in the primary circuit of the electromagnet.

7. The combination of two diaphragms, one having the capacity ofreceiving and transmiting sound-waves and the other acting as acontact-spring to' maintain the continuity of the circuit.

8.v The combination of two yielding diaphragms and interposedconducting-buttons, each secured upon its respective diaphragm and withtheir adjacent faces in contact, whereby their pressure upon each othermay be readily adjusted and maintained. i

JOHN H. IRWIN.

KVitnesses CHAS. F.' R. HEUOKEROTH, WILLIAM L. VOELKER.

